Racks have long been used for moving supported objects from one place to another.
Known racks and frames are disclosed in, for example: U.S. Pat. No. 5,330,064 to Hall; U.S. Pat. No. 3,912,086 to de Bruyn; U.S. Pat. No. 5,330,060 to Bohner; U.S. Pat. No. 5,123,550 to Nodskov et al.; U.S. Pat. No. 5,016,765 to Leonardo; and U.S. Pat. No. 4,349,213 to Hirsch.
Known racks are frequently expensive to manufacture, unsuitable for various load and force requirements, difficult to use, often require lots of storage space, particularly in case of heavy-duty racks, and are difficult to assemble and disassemble.